Genetic assessment of connectivity in the temperate octocorals Eunicella verrucosa and Alcyonium digitatum in the NE Atlantic
Holland, Lyndsey Paula
Date: 12 April 2013
Publisher
University of Exeter
Degree Title
PhD in Biological Sciences
Abstract
Elucidating patterns of connectivity for species of conservation concern is crucial in the design
of networks of ecologically coherent marine protected areas, and therefore is considered in
the design of such a network recently proposed to the UK Government. However, data
concerning connectivity are deficient for most invertebrate ...
Elucidating patterns of connectivity for species of conservation concern is crucial in the design
of networks of ecologically coherent marine protected areas, and therefore is considered in
the design of such a network recently proposed to the UK Government. However, data
concerning connectivity are deficient for most invertebrate sessile taxa. Therefore, this study
used microsatellite panels developed de novo to assess the population genetic structure and
genetic connectivity of two temperate octocorals in the North East Atlantic. Microsatellite
panels for both species show evidence of cross-species transferability, and therefore in future
may prove to be useful monitoring tools for the target species but also for congenerics further
afield in Europe.
Eunicella verrucosa (O. Alcyonacea: S.O.Holaxonia: F. Gorgoniidae), a threatened and IUCN
red-listed sea fan, was sampled in the northerly extremes of its eastern Atlantic range in
southern Portugal, Brittany, the South West UK and western Ireland. In this vicinity,
connectivity appears to be defined at regional scales and localised cases of inbreeding and
differentiation suggest that the population structure of this species is best described as a
metapopulation. Alcyonium digitatum (O. Alcyonacea: S.O. Alcyoniina: F. Alcyoniidae), a soft
coral, was sampled in the central portion of its range in Brittany, western Ireland, south west
UK and the North Sea. This species exhibited very little population structure and apparent
panmixia across the sampled range. However, high levels of heterozygote deficiencies and
inbreeding in the majority of populations implies that the genetic structure of some
populations of this species may be defined by self-seeding and rarer dispersal events that
occur sufficiently often to offset divergence via genetic drift. Coalescent analyses indicate that
in both species, migration between regions occurs asymmetrically. The presence of few
duplicate genotypes in both datasets implies that sexual reproduction predominates in both
species in the sampled area. Eunicella verrucosa is a charismatic species that is often used to
promote marine conservation efforts in the UK and A. digitatum is a ubiquitous animal around
western European coasts; the two species often occur together and both may suffer the
damaging effects of mobile fishing gears. This research represents the first population genetic
assessment of both species and the first time microsatellites have been used to assess
population structure of octocorals in the North East Atlantic.
Doctoral Theses
Doctoral College
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